Kaons – (or K mesons) atomic particles whose decay products are mesons only

Kelvin temperature scale – a scale to measure temperature based on absolute zero as the lowest possible temperature

Keplers laws of planetary motion - laws defining the orbits and periods of objects in space. (see Section 5.3)

Kinetic energy – the energy of motion

Kinetic theory of gases – gases are made up of a large number of small spherical molecules, in random motion , that have only elastic collisions with each other and with the walls of the container

Kinematics – the description ( or study) of motion, without regard to the causes of the motion

Kirchhoff’s rules – an application of the concept of conservation of energy and conservation of charge to electric circuits (see Section 18.6)